Model analysis of the factors regulating the trends and variability of carbon monoxide between 1988 and 1997

Duncan, B. N.; Logan, Jennifer A.

doi:10.5194/acp-8-7389-2008

Cited by 76 publications

(70 citation statements)

References 47 publications

(74 reference statements)

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“…Global CO concentrations peaked in the late 1980s, followed by a decline through the 1990s and relatively stable levels through the 2000s. The most pronounced decline was in the NH, apparently related to emission reductions in N. America and Europe (Novelli et al, 2003;Duncan and Logan, 2008). The observed 2009-1987 difference of about 10 ppb in northerly tropical regions, and the near-identical values in the southerly region, closely match the trends observed by the global monitoring networks in the NH and SH tropics, respectively (Duncan and Logan, 2008).…”

Section: Barca-b: Late Wet Seasonsupporting

confidence: 58%

“…While at the global and annual scale the four main CO sources are of comparable magnitude, their spatial and temporal variations result in distinctive spatio-temporal patterns of the atmospheric distribution of CO. The oxidation of CH 4 , a long-lived trace gas with fairly even global distribution, results in an almost uniform CO background of about 25 ppb worldwide, whereas fossil fuel derived emissions dominate in the northern mid-latitudes (Holloway et al, 2000;Duncan and Logan, 2008). On a seasonal time scale, fossil fuel emissions dominate CO sources in winter in North America, while oxidation of CH 4 (35 %) and biogenic nonmethane VOCs (21 %), among which isoprene makes by far the largest contribution, are the largest sources of CO in summer .…”

Section: Introductionmentioning

confidence: 99%

“…VOC oxidation shows relatively little seasonal and spatial variability over the tropical continents, and thus provides a relatively smooth background, which may account for a considerable fraction of the CO burden in the lower troposphere there (Holloway et al, 2000;Duncan and Logan, 2008). In contrast, biomass burning occurs mainly during the dry season and along the margins of the rain forest.…”

Section: Introductionmentioning

confidence: 99%

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Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

Artaxo²,

et al. 2012

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Abstract. We present the results of airborne measurements of carbon monoxide (CO) and aerosol particle number concentration (CN) made during the Balanço Atmosférico Regional de Carbono na Amazônia (BARCA) program. The primary goal of BARCA is to address the question of basinscale sources and sinks of CO 2 and other atmospheric carbon species, a central issue of the Large-scale BiosphereAtmosphere (LBA) program. The experiment consisted of two aircraft campaigns during November-December 2008 (BARCA-A) and May-June 2009 (BARCA-B), which covered the altitude range from the surface up to about 4500 m, and spanned most of the Amazon Basin.Based on meteorological analysis and measurements of the tracer, SF 6 , we found that airmasses over the Amazon Basin during the late dry season (BARCA-A, November 2008) originated predominantly from the Southern Hemisphere, while during the late wet season (BARCA-B, May 2009) low-level airmasses were dominated by northernhemispheric inflow and mid-tropospheric airmasses were of mixed origin. In BARCA-A we found strong influence of biomass burning emissions on the composition of the atmosphere over much of the Amazon Basin, with CO enhancements up to 300 ppb and CN concentrations approaching 10 000 cm −3 ; the highest values were in the southern part of the Basin at altitudes of 1-3 km. The CN/ CO ratios were diagnostic for biomass burning emissions, and were lower in aged than in fresh smoke. Fresh emissions indicated CO/CO 2 and CN/CO emission ratios in good agreement with previous work, but our results also highlight the need to consider the residual smoldering combustion that takes place after the active flaming phase of deforestation fires.During the late wet season, in contrast, there was little evidence for a significant presence of biomass smoke. Low CN concentrations (300-500 cm −3 ) prevailed basinwide, and CO mixing ratios were enhanced by only ∼10 ppb above the mixing line between Northern and Southern Hemisphere air. There was no detectable trend in CO with distance from the coast, but there was a small enhancement of CO in the boundary layer suggesting diffuse biogenic sources from photochemical degradation of biogenic volatile organic compounds or direct biological emission.Simulations of CO distributions during BARCA-A using a range of models yielded general agreement in spatial distribution and confirm the important contribution from biomass burning emissions, but the models evidence some systematic quantitative differences compared to observed CO concentrations. These mismatches appear to be related to problems with the accuracy of the global background fields, the role Published by Copernicus Publications on behalf of the European Geosciences Union. M. O. Andreae et al.: Carbon monoxide and related trace gases and aerosolsof vertical transport and biomass smoke injection height, the choice of model resolution, and reliability and temporal resolution of the emissions data base.

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Section: Barca-b: Late Wet Seasonsupporting

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

Artaxo²,

et al. 2012

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“…Measuring the variability and trends in carbon monoxide (CO) on the global scale is essential as it is an ozone and carbon dioxide precursor, and it regulates the oxidizing capacity of the troposphere through its destruction cycle involving the hydroxyl radical (OH) (Duncan and Logan, 2008). The background CO atmospheric loading varies as a function of season and latitude and is significantly perturbed by human activities related to combustion processes: car traffic, heating/cooking systems, industrial activities, etc.…”

Section: Introductionmentioning

confidence: 99%

An examination of the long-term CO records from MOPITT and IASI: comparison of retrieval methodology

et al. 2015

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Abstract. Carbon monoxide (CO) is a key atmospheric compound that can be remotely sensed by satellite on the global scale. Fifteen years of continuous observations are now available from the MOPITT/Terra mission (2000 to present). Another 15 and more years of observations will be provided by the IASI/MetOp instrument series (2007-2023 >). In order to study long-term variability and trends, a homogeneous record is required, which is not straightforward as the retrieved quantities are instrument and processing dependent. The present study aims at evaluating the consistency between the CO products derived from the MOPITT and IASI missions, both for total columns and vertical profiles, during a 6-year overlap period (2008)(2009)(2010)(2011)(2012)(2013). The analysis is performed by first comparing the available 2013 versions of the retrieval algorithms (v5T for MOPITT and v20100815 for IASI), and second using a dedicated reprocessing of MO-PITT CO profiles and columns using the same a priori information as the IASI product. MOPITT total columns are generally slightly higher over land (bias ranging from 0 to 13 %) than IASI data. When IASI and MOPITT data are retrieved with the same a priori constraints, correlation coefficients are slightly improved. Large discrepancies (total column bias over 15 %) observed in the Northern Hemisphere during the winter months are reduced by a factor of 2 to 2.5. The detailed analysis of retrieved vertical profiles compared with collocated aircraft data from the MOZAIC-IAGOS network, illustrates the advantages and disadvantages of a constant vs. a variable a priori. On one hand, MOPITT agrees better with the aircraft profiles for observations with persisting high levels of CO throughout the year due to pollution or seasonal fire activity (because the climatology-based a priori is supposed to be closer to the real atmospheric state). On the other hand, IASI performs better when unexpected events leading to high levels of CO occur, due to a larger variability associated with the a priori.

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“…Carbon monoxide (CO) emissions follow those of Duncan et al (2007) and Duncan and Logan (2008). The Global Modeling Initiative chemistry and transport model simulations were used to calculate methane and hydroxyl climatologies to estimate chemical production and loss in a computationally efficient manner.…”

Section: Geos-5 Trace Gas and Aerosol Emissionsmentioning

confidence: 99%

Impact of planetary boundary layer turbulence on model climate and tracer transport

et al. 2015

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Abstract. Planetary boundary layer (PBL) processes are important for weather, climate, and tracer transport and concentration. One measure of the strength of these processes is the PBL depth. However, no single PBL depth definition exists and several studies have found that the estimated depth can vary substantially based on the definition used. In the Goddard Earth Observing System (GEOS-5) atmospheric general circulation model, the PBL depth is particularly important because it is used to calculate the turbulent length scale that is used in the estimation of turbulent mixing. This study analyzes the impact of using three different PBL depth definitions in this calculation. Two definitions are based on the scalar eddy diffusion coefficient and the third is based on the bulk Richardson number. Over land, the bulk Richardson number definition estimates shallower nocturnal PBLs than the other estimates while over water this definition generally produces deeper PBLs. The near-surface wind velocity, temperature, and specific humidity responses to the change in turbulence are spatially and temporally heterogeneous, resulting in changes to tracer transport and concentrations. Near-surface wind speed increases in the bulk Richardson number experiment cause Saharan dust increases on the order of 1 × 10 −4 kg m −2 downwind over the Atlantic Ocean. Carbon monoxide (CO) surface concentrations are modified over Africa during boreal summer, producing differences on the order of 20 ppb, due to the model's treatment of emissions from biomass burning. While differences in carbon dioxide (CO 2 ) are small in the time mean, instantaneous differences are on the order of 10 ppm and these are especially prevalent at high latitude during boreal winter. Understanding the sensitivity of trace gas and aerosol concentration estimates to PBL depth is important for studies seeking to calculate surface fluxes based on near-surface concentrations and for studies projecting future concentrations.

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Model analysis of the factors regulating the trends and variability of carbon monoxide between 1988 and 1997

Cited by 76 publications

References 47 publications

Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

An examination of the long-term CO records from MOPITT and IASI: comparison of retrieval methodology

Impact of planetary boundary layer turbulence on model climate and tracer transport

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